電容分壓器工作原理：

電(dian)(dian)容分(fen)(fen)壓(ya)器(qi)因為(wei)相對普通電(dian)(dian)阻式分(fen)(fen)壓(ya)器(qi)的耐壓(ya)強度大，不(bu)易擊(ji)穿，一般用(yong)來測(ce)量交流高壓(ya)。但(dan)由于其頻響效應(ying)的響應(ying)時間值比電(dian)(dian)阻分(fen)(fen)壓(ya)器(qi)大，所以(yi)在(zai)沖(chong)擊(ji)電(dian)(dian)壓(ya)的測(ce)量中(zhong)比電(dian)(dian)阻分(fen)(fen)壓(ya)器(qi)用(yong)的少，對于特高沖(chong)擊(ji)電(dian)(dian)壓(ya)的測(ce)量經(jing)常用(yong)阻容分(fen)(fen)壓(ya)器(qi)。用(yong)于測(ce)量沖(chong)擊(ji)電(dian)(dian)壓(ya)。

　　電容分壓器由高壓臂電容C1和低壓臂電容C2組成。電容分壓器利用(yong)電(dian)容分壓(ya)原理實現(xian)電(dian)壓(ya)變換，將高壓(ya)分為(wei)低壓(ya)并進行A/D 變換，經(jing)電(dian)/光轉換耦合進行光纖傳輸(shu)， 傳至信(xin)號處理單元進行光/電(dian)轉換，經(jing)微(wei)機系(xi)統處理輸(shu)出數(shu)字信(xin)號或進行D/A 轉換輸(shu)出模擬信(xin)號。其(qi)工作原理如圖所示：

　　實(shi)用電(dian)路(lu)中不只是電(dian)阻器可以(yi)構成(cheng)分壓(ya)電(dian)路(lu)，其他許多元器件都可構成(cheng)分壓(ya)電(dian)路(lu)，在交流電(dian)路(lu)中也有用電(dian)容構成(cheng)的分壓(ya)電(dian)路(lu)。

　　如上(shang)圖所示是(shi)電(dian)容分壓(ya)(ya)電(dian)路。電(dian)路中，Cl和C2構成電(dian)容分壓(ya)(ya)電(dian)路，Ui是(shi)交流(liu)輸(shu)入信(xin)號(hao)(hao)電(dian)壓(ya)(ya)，Uo是(shi)輸(shu)出信(xin)號(hao)(hao)電(dian)壓(ya)(ya)，輸(shu)出信(xin)號(hao)(hao)電(dian)壓(ya)(ya)取出電(dian)容C2上(shang)。

　電(dian)阻分(fen)壓(ya)電(dian)路(lu)是各(ge)種分(fen)壓(ya)電(dian)路(lu)中最(zui)基本的(de)電(dian)路(lu)，分(fen)析電(dian)容分(fen)壓(ya)電(dian)路(lu)等時(shi)可(ke)以運用分(fen)析電(dian)阻分(fen)壓(ya)電(dian)路(lu)的(de)基本思路(lu)和方法，再借(jie)助電(dian)容器的(de)具體特性進行(xing)個(ge)性分(fen)析。

　　關于電容分壓電路的(de)分析(xi)思路和方(fang)法說明下列幾點：

　　(1)由于電(dian)容的隔直(zhi)特(te)性，所(suo)以這一(yi)分壓電(dian)路不適合于直(zhi)流電(dian)路。

　　(2)電(dian)容分(fen)(fen)壓電(dian)路的信號輸(shu)入(ru)、輸(shu)出方(fang)(fang)式與電(dian)阻分(fen)(fen)壓電(dian)路一樣(yang)，電(dian)路分(fen)(fen)析的方(fang)(fang)法相(xiang)同，電(dian)阻分(fen)(fen)壓電(dian)路的分(fen)(fen)析方(fang)(fang)法是各種(zhong)形式分(fen)(fen)壓電(dian)路分(fen)(fen)析方(fang)(fang)法的基礎(chu)。

　　(3)進行輸出電(dian)(dian)壓大小(xiao)(xiao)分(fen)(fen)(fen)析時，運用等效(xiao)理解方(fang)(fang)法，見電(dian)(dian)路(lu)右側的(de)等效(xiao)電(dian)(dian)路(lu)，電(dian)(dian)容Cl和C2的(de)容抗(kang)分(fen)(fen)(fen)析用兩只電(dian)(dian)阻來等效(xiao)，這樣電(dian)(dian)容分(fen)(fen)(fen)壓電(dian)(dian)路(lu)就(jiu)等效(xiao)成電(dian)(dian)阻分(fen)(fen)(fen)壓電(dian)(dian)路(lu)，可以(yi)用電(dian)(dian)阻分(fen)(fen)(fen)壓電(dian)(dian)路(lu)中分(fen)(fen)(fen)析輸出電(dian)(dian)壓大小(xiao)(xiao)的(de)方(fang)(fang)法來分(fen)(fen)(fen)析。

　　(4)等效電路(lu)的(de)分析(xi)中關(guan)(guan)鍵是容(rong)抗(kang)大(da)小的(de)理解，這里需(xu)要了解電容(rong)容(rong)抗(kang)的(de)有(you)關(guan)(guan)特性，容(rong)抗(kang)與頻(pin)率成反比，容(rong)抗(kang)與容(rong)量(liang)成反比。不(bu)了解容(rong)抗(kang)與頻(pin)率、容(rong)量(liang)之間的(de)關(guan)(guan)系就無法進行這種等效分析(xi)，許多初學者電路(lu)分析(xi)中遇到困難也是出于(yu)對這些基本(ben)知(zhi)識和概(gai)念的(de)掌握不(bu)全面(mian)、不(bu)扎實。

　　(5)流過電(dian)容(rong)(rong)分壓(ya)(ya)電(dian)路(lu)各(ge)電(dian)容(rong)(rong)的(de)(de)(de)(de)信號(hao)頻(pin)率相(xiang)(xiang)同，這(zhe)樣進行等(deng)(deng)效(xiao)電(dian)路(lu)分析(xi)時(shi)只需要考慮C1、C2的(de)(de)(de)(de)容(rong)(rong)量大小(xiao)對(dui)容(rong)(rong)抗的(de)(de)(de)(de)影(ying)響。如果C1的(de)(de)(de)(de)容(rong)(rong)量等(deng)(deng)于(yu)C2的(de)(de)(de)(de)容(rong)(rong)量，那么C1和C2的(de)(de)(de)(de)容(rong)(rong)抗相(xiang)(xiang)等(deng)(deng)，即(ji)等(deng)(deng)效(xiao)電(dian)路(lu)中(zhong)的(de)(de)(de)(de)R C1、R C2相(xiang)(xiang)等(deng)(deng)，由前面電(dian)阻分壓(ya)(ya)電(dian)路(lu)特性可知，此時(shi)輸出電(dian)壓(ya)(ya)Uo等(deng)(deng)于(yu)輸入電(dian)壓(ya)(ya)Ui的(de)(de)(de)(de)一半;當電(dian)容(rong)(rong)C1的(de)(de)(de)(de)容(rong)(rong)量大于(yu)C2的(de)(de)(de)(de)容(rong)(rong)量時(shi)，C1的(de)(de)(de)(de)容(rong)(rong)抗R C1小(xiao)于(yu)C2的(de)(de)(de)(de)容(rong)(rong)抗RC2，此時(shi)輸出電(dian)壓(ya)(ya)Uo大于(yu)輸入電(dian)壓(ya)(ya)Ui的(de)(de)(de)(de)一半。

　　(6)分壓(ya)(ya)電(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)(lu)其實(shi)質是為了(le)將(jiang)較大的輸(shu)(shu)入(ru)信(xin)號(hao)(hao)電(dian)(dian)(dian)(dian)壓(ya)(ya)適(shi)當(dang)衰減(jian)，得到一個比輸(shu)(shu)入(ru)電(dian)(dian)(dian)(dian)壓(ya)(ya)小的輸(shu)(shu)出(chu)電(dian)(dian)(dian)(dian)壓(ya)(ya)。在交(jiao)流(liu)電(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)(lu)中(zhong)，分壓(ya)(ya)電(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)(lu)是用(yong)來將(jiang)輸(shu)(shu)入(ru)的交(jiao)流(liu)信(xin)號(hao)(hao)進行(xing)適(shi)當(dang)的衰減(jian)，可以采用(yong)電(dian)(dian)(dian)(dian)阻(zu)分壓(ya)(ya)電(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)(lu)實(shi)現(xian)這一電(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)(lu)功(gong)能，為何又要采用(yong)電(dian)(dian)(dian)(dian)容(rong)(rong)分壓(ya)(ya)電(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)(lu)?因為電(dian)(dian)(dian)(dian)阻(zu)對(dui)(dui)信(xin)號(hao)(hao)存(cun)在損(sun)耗(hao)(hao)，而電(dian)(dian)(dian)(dian)容(rong)(rong)在理論上對(dui)(dui)信(xin)號(hao)(hao)能量不存(cun)在損(sun)耗(hao)(hao)，所以在一些交(jiao)流(liu)信(xin)號(hao)(hao)電(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)(lu)中(zhong)，特別是高(gao)頻信(xin)號(hao)(hao)電(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)(lu)中(zhong)采用(yong)電(dian)(dian)(dian)(dian)容(rong)(rong)分壓(ya)(ya)電(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)(lu)而不用(yong)電(dian)(dian)(dian)(dian)阻(zu)分壓(ya)(ya)電(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)(lu)。